'Based on a true story' isn't a phrase that only applies to books and movies. It also applies to our conceptions of the past. We're constantly compelled to fit what we know, or think we know, about the past into some kind of narrative. Unfortunately, both those facts and that narrative are sometimes wrong. Dr. Marlene Zuk joins us to discuss her book, Paleofantasies: What Evolution Really Tells Us About Sex, Diet, and How We Live.